Is it Legally Enforceable?
Yes, the monetary portion of a cohabitation agreement is legally enforceable if it is entered voluntarily by both parties, supported by valid consideration, and not based solely on the exchange of sexual services.
This is supported by the California Supreme Court case Marvin v. Marvin (1976), which mentions explicitly:
Adults who voluntarily live together and engage in sexual relations are not barred from enforcing agreements relating to earnings, property, or support, so long as the agreement is not explicitly founded on meretricious consideration.
How to Make a Relationship Contract (8 steps)
1. Exclusivity

Decide if the partners will be sexually active with other people: (choose one)
- Exclusive: No other sexual partners.
- Open: Other sexual partners are allowed. Protection during such interaction should be required.
- Custom: Some partners have exclusive relationships except for maybe one (1) “free pass” per year.






